Plastic pallet

ABSTRACT

This invention relates to a tray-like pallet made of stiff plastic material and suitable for use in the setting up of a stack of identical containers each having a top with an outline capable of providing support and different in area from the outline of the bottom thereof, the said pallet having on one face a plurality of non-interconnected projection means between a number of which the base of each container of a series of containers forming a single tier of the stack can be sufficiently confined to produce a stable stack, and having on the other face a plurality of projection means between a number of which the top of each container of a series of containers forming a lower tier of the stack also can be sufficiently confined to produce a stable stack, the pallet being in addition so formed that a plurality thereof are stackable when not in use.

United States Patent [1 1 Fleischer et al.

[451 Sept. 4, 1973 I PLASTIC PALLET [73] Assignee: Kalle Aktiengesellschaft,

Wiesbaden-Biebrich, Germany [22] Filed: Dec. 7, 1971 [211 Appl. No.: 205,640

{30] Foreign Application Priority Data Dec. 9, 1970 Germany P 20 60 563.4

[52] US. Cl. 2l4/l0.5 R, 206/65 R, 220/97 B [51] Int. Cl. B65g 1/14 [58] Field of Search 2l4/l0.5 R; 206/65 R, 65 Y; 220/97 B; 229/42; 217/265 [56] References Cited UNITED STATES PATENTS 3,250,564 5/l966 Stern et al 220/97 B X 3,35l,264 ll/l967 Bostrom 220/97 B X FOREIGN PATENTS OR APPLICATIONS l,l30,8l2 l0/l968 Great Britain 206/65 R 645,857 7/1962 Canada 217/26 S Primary Examiner-Gerald M. Forlenza Assistant Examiner-Frank E. Werner Attorney-James E. Bryan [5 7 ABSTRACT This invention relates to a tray-like pallet made of stiff plastic material and suitable for use in the setting up of a stack of identical containers each having a top with an outline capable of providing support and different in area from the outline of the bottom thereof, the said pallet having on one face a plurality of noninterconnected projection means between a number of which the base of each container of a series of containers forming a single tier of the stack can be sufficiently confined to produce a stable stack, and having on the other face a plurality of projection means between a number of which the top of each container of a series of containers forming a lower tier of the stack also can be sufficiently confined to produce a stable stack, the pallet being in addition so formed that a plurality thereof are stackable when not in use.

14 Claims, 4 Drawing Figures PLASTIC PALLET ,This invention relates to a pallet of plastic material for holding containers, especially beakers, and more particularly for setting up stacks of such containers.

Apart from the customary wooden racks, a variety of pallets have been developed for sorting, stacking and transporting containers, such as beakers filled with dairy products or fruit juice drinks. A large number consist of corrugated paper and/or cardboard or Styropor (foamed polystyrene) of a particular shape.

ln the case of cardboard pallets, a distinction is made between corrugated paper carriers with cardboard insert, and simple folded pallets made of cardboard. While these are usable for stacking containers, they have the disadvantage that the user must first erect or assemble them. Equally, their sensitivity to moisture is a disadvantage which must not be underestimated.

In factories handling wet materials, such as, for example dairies or fruit juice filling factories, complete softening of the pallet through spilled liquid material frequently occurs, and this causes considerable problems in machine operation and/or makes subsequent transportation impossible. A further defect of these cardboard pallets is that when stacking filled containers they permit only relative low stacking heights, since there is only one cardboard interlayer. This height is restricted by the fact that the individual layers cannot become fixed, or can become only poorly fixed, relative to one another, that is to say with about superposed layers the construction becomes so unstable that it slips sideways, or falls over, above all on being tipped slightly.

Furthermore, plastic pallets are known wherein the containers to be inserted are inserted into appropriately fitting recesses which peripherally confine the container. Since the recesses are matched to the shape of the containers to be manufactured, the insertion of the containers into the pallet is expensive as regards machine construction, which must be such as to ensure accurate insertion. If the container is slightly displaced relative to the pallet, as a result of slight inaccuracies in the machine guide mechanism, or as a result of deformation of the beakers supplied and as a result of possible errors in operation, the containers are introduced in a displaced or angled position relative to the pallet, as a result of which both are destroyed. This results in time-consuming machine stoppages in addition to the obvious economic losses.

A further disadvantage of the known plastic pallets is that when present in a stack they can easily slip and thus only very low stacking heights are achievable. Unless additionally an interlayer, preferably of cardboard, is also inserted, the edges, which are often very sharp, can destroy the mostly very thin lids of the filled containers, as a result of which the contents, for example dairy products, may spoil.

Apertured pallets of Styropor are also very suitable for transportation but have the great disadvantage that the empty pallets are very bulky in transportation and storage. Where several thousand pallets per day are required, this means that the user either has to provide an uneconomical amount of storage space or make use of equally uneconomical daily delivery.

Styropor pallets can, however, be constructed to be themselves stackable, since they are molded in such a way that they engage with one another when stacked and hence do not permit lateral displacement. The total thickness of the material of the pallet must be made considerable, especially at the locking points, since Styropor is very prone to break and hence relatively easily destroyed.As a result, the pallet spacing, from layer to layer, is 5 to 20 mm. When the space availability restricts the stacking height, far fewer layers can be placed on top of one another than in the case of cardboard pallets, which again is regarded as a considerable shortcoming.

A further considerable disadvantage is the fact that as a result of the accurately fixed holes the same difficulties arise in using machines as have been described above for the unfoarned plastic pallets. Furthermore, only frusto-conical containers diverging in an upward direction can be accommodated.

The present invention provides a tray-like pallet made of stiff plastic material and suitable for use in the setting up of a stack of identical containers each having a top with an outline capable of providing support and different area from the outline of the bottom thereof, the pallet having on one face a multiplicity of noninterconnected projections between a plurality of which the base of each container of a series of containers forming a single tier of the stack can be sufficiently confined to produce a stable stack, and having on the other face a multiplicity of projections between a pluraity of which the top of each container of a series of containers forming a lower tier of the stack also can be sufficiently confined to produce a stable stack, the pallet being in addition so formed that a plurality thereof are stackable when not in use.

In the case of a pallet intended to confine the tops of the containers with tapered sides diverging towards the top, the projections intended to confine the bottoms of the containers are preferably made of a height which is more than 15 percent of the height of the container to be confined.

The projections intended to confine the tops of the containers are advantageously 0.5 to 50 mm, preferably 3 to 10 mm in height.

In the case of the pallet according to the invention, on arranging the containers, especially beakers, thereon, the latter are centered between two or more of the projections, or raised portions, on the upper side of the pallet and on superposing a further pallet the upper edge portions of the beakers are confined by two or more of the projections, or depressed portions, on the underside of this latter pallet, so that lateral slipping is impossible.

It has been found in practice that 20 or more pallets occupied by containers can be stacked on top of one another and, for example, even in the case of an inclination of 10 to 15, as repeatedly occurs during transportation of such a stack, lateral slipping does not take place.

The pallet according to the invention is especially useful in factories which palletize liquid goods, as, for example, dairies, fruit juice packing stations and similar factories.

For dairies, for example, the plastic pallet of the invention, being moisture-insensitive, has a further advantage over cardboard containers owing to the fact that, for example, yoghurt can be further incubated in climatically controlled cabinets without an additional working step. As a result of the temperature changes, the containers become moist. Packaging in cardboard pallets was therefore hitherto possible only after the incubation process, Which required an additional process step. When using the plastic pallet of the invention, the latter is employed immediately after filling the beakers. The stack consisting of several layers can be passed directly to the incubation process. After this process the product can be delivered directly since repacking is unnecessary. To simplify or speed up the incubation, the pallet can possess a number of perforations. The warm air thus can flow through the pallet in a vertical direction as well as horizontally. The containers are thus uniformly subjected to the effects of the warm air.

A further advantage results from the fact that the pallet is so constructed that the stacking pressure to which the lowest container is exposed is borne by the container wall. The usual aluminum foil lid, which in the case of such beakers is mostly thin, is thus not subjected to load, though all the containers, which are in most cases of conical shape, stand vertically one above another.

In a further development of the pallet, the projections on either or both faces are resiliently deformable. This results in the advantage that even if the containers are inaccurately introduced into the pallet, good centering becomes possible since the projections can yield somewhat and subsequently resume their previous position which effects centering. This avoids stoppage of the working sequence even if the machine runs inaccurately.

The he ght of the projections referred to above as raised portions, for secure centering and avoidance of slipping of the individual beakers, admittedly can be relatively low, but as regards slipping of the filled pallets stacked on top of one another, and the associated danger of tipping of the beakers and hence of the entire stack, the height of the raised portions should be at least l5 percent of the height of the container introduced. There is no upper limit to the height of the raised portions but it has been found in practice that for the purpose of optimum material utilization the height of the raised portions should be to 50 percent of the height of the containers to be introduced.

The shape of the projections is capable of extensive variation so long as the requirement of good centering of the entire stack is met. In order to attain an attractive optical impression and not to make the tools for the manufacture of the pallet unnecessarily complicated, it has proved advantageous for the projections, that is the raised and/or depressed portions, all to be of equal height and/or the same shape.

As a further development, the pallet may possess stiffening portions between the projections, in order to make the pallet more resistant to twisting, above all if it is made in fairly low thicknesses. The stiffening portions then simultaneously serve as spacing portions between the base of the pallet and the container which is to be introduced.

Though there are no particular restrictions as to the method of manufacture, since the pallet can, for example, be case or injection molded, the pallet is nevertheless particularly advantageously manufactured by the deep-drawing process. In particular, a deep-drawing ratio of width to height of the raised and/or depressed portions and/or of the stiffening portions of 5 I to I 5, preferably 2.5 l to l 2.5, is observed.

Though the overall shape of the pallet is not subject to any restriction, a rectangular base section is preferably provided because of its greater simplicity in working with machinery.

In order to achieve further stiffening of the pallet, especially in the case of thinner materials, a particular embodiment of the pallet has an interrupted or continuous peripheral rim, this rim preferably running perpendicular or almost perpendicular to the general plane of the pallet.

In order to provide, for example, names, prices, packaging dates and the like, or to design the pallet with a view to an optically attractive effect, embossings and/or printing may be present in any flat portion and- /or projection and/or the rim.

A colored pallet obtainable by using colored, especially pigmented, material, for the manufacture of the pallet.

Though there is no particular restriction as to the plastic material for the pallet, provided it can be cast, injection-moulded or deep-drawn, the use of polystyrene or polyvinyl chloride or copolymers of the corresponding monomers is nevertheless preferred for the manufacture of the pallets.

The invention is illustrated by way of example in the accompanying drawings, in which:

FIG. 1 is a plan view of a pallet,

FIG. 2 is a section on the line A B of FIG. 1,

FIG. 3 is a plan view of a second embodiment showing only two of the raised portions and FIG. 4 shows several pallets of identical shape in a stack of containers.

Referring to the drawings, FIG. I shows a rectangular pallet with projections in the form of raised portions 2 between which are shown in broken lines the outlines of the bases of inserted containers 3. Round orifices 5 are provided in the raised portions 2. Stiffening portions 6 are provided between the raised portions. The pallet has a peripheral rim 7.

FIG. 2 shows the pallet base 1 with the raised portions 2 and with depressed portions 4. h, is the height of the container and h, and h, the heights of the portions 2 and 4 respectively.

FIG. 3 shows a different form of the raised portions 2, again provided with orifices 5. For clarity, only two raised portions are shown.

FIG. 4 shows three pallets of identical shape in a regular stack of containers one layer on top of another.

It will be obvious to those skilled in the art that many modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.

What is claimed is:

1. A tray-like pallet made of stiff plastic material and suitable for use in setting up a stack of identical containers each having a top with an outline capable of providing support and different in area from the outline of the bottom thereof, said pallet having a generally planar base, a plurality of non-interconnected projection means on one face, between a number of which the base of each container of a series of containers, fonning a single tier of said stack, can be sufficiently confined to produce a stable stack, and having a plurality of projection means on the other face, between a number of which the top of each container of a series of containers, forming a lower tier of said stack can also be sufficiently confined to produce a stable stack, said projection means of said two faces being arranged with respect to one another in a manner such that the bottom of each of the upper containers in said stack and the cover of each of the underneath containers in said stack are in direct contact with said planar base of said pallet and that the bottoms and covers of the stacked containers are fully supported by said planar base and spaced from one another by the thickness of said planar base only and said pallet is also formed in a manner that a plurality of said pallets are stackable when not in use.

2. A pallet as claimed in claim 1, for the support of containers with tapered sides diverging towards the top, in which pallet the projections intended to confine the bottoms of the containers are made of a height which is more than percent of the height of the container to be confined.

3. A pallet as claimed in claim 1, for the support of containers with tapered sides diverging towards the top, in which pallet the projections intended to confine the bottoms of the containers are made of a height which is more than to 50 percent of the height of the container to be confined.

4. A pallet as claimed in claim 2, in which the projections intended to confine the tops of the containers are 0.5 to 50 mm in height.

5. A pallet as claimed in claim 2, in which the projections intended to confine the tops of the containers are 3 to 10 mm in height.

6. A pallet as claimed in claim 1, of which the projections on either or both faces are resiliently deformable.

7. A pallet as claimed in claim ll, including orifice means arranged for air passage between tiers of containers when in a stack thereof.

8. A pallet as claimed in claim 7, in which said orifices are in the projections on either or both faces.

9. A pallet as claimed in claim 1, including stiffening portions between the projections intended to confine the tops of the containers.

10. A pallet as claimed in claim 1, made from a sheet of plastic material by deep-drawing.

11. A pallet as claimed in claim 10, having a deepdrawing ratio of width height of any deformation produced by the deep-drawing operation of 5:1 to 1:5.

12. A pallet as claimed in claim 10, having a deepdrawing ratio of width height of any deformation produced by the deep-drawing operation of 2.5:] to 1:25

13. A pallet as claimed in claim 1, including a continuous or interrupted peripheral rim turned out of the general plane of the pallet.

14. A pallet as claimed in claim 1, made of polystyrene or polyvinyl chloride or a copolymer of the corresponding monomers. 

1. A tray-like pallet made of stiff plastic material and suitable for use in setting up a stack of identical containers each having a top with an outline capable of providing support and different in area from the outline of the bottom thereof, said pallet having a generally planar base, a plurality of noninterconnected projection means on one face, between a number of which the base of each container of a series of containers, forming a single tier of said stack, can be sufficiently confined to produce a stable stack, and having a plurality of projection means on the other face, between a number of which the top of each container of a series of containers, forming a lower tier of said stack can also be sufficiently confined to produce a stable stack, said projection means of said two faces being arranged with respect to one another in a manner such that the bottom of each of the upper containers in said stack and the cover of each of the underneath containers in said stack are in direct contact with said planar base of said pallet and that the bottoms and covers of the stacked containers are fully supported by said planar base and spaced from one another by the thickness of said planar base only and said pallet is also formed in a manner that a plurality of said pallets are stackable when not in use.
 2. A pallet as claimed in claim 1, for the support of containers with tapered sides diverging towards the top, in which pallet the projections intended tO confine the bottoms of the containers are made of a height which is more than 15 percent of the height of the container to be confined.
 3. A pallet as claimed in claim 1, for the support of containers with tapered sides diverging towards the top, in which pallet the projections intended to confine the bottoms of the containers are made of a height which is more than 20 to 50 percent of the height of the container to be confined.
 4. A pallet as claimed in claim 2, in which the projections intended to confine the tops of the containers are 0.5 to 50 mm in height.
 5. A pallet as claimed in claim 2, in which the projections intended to confine the tops of the containers are 3 to 10 mm in height.
 6. A pallet as claimed in claim 1, of which the projections on either or both faces are resiliently deformable.
 7. A pallet as claimed in claim 1, including orifice means arranged for air passage between tiers of containers when in a stack thereof.
 8. A pallet as claimed in claim 7, in which said orifices are in the projections on either or both faces.
 9. A pallet as claimed in claim 1, including stiffening portions between the projections intended to confine the tops of the containers.
 10. A pallet as claimed in claim 1, made from a sheet of plastic material by deep-drawing.
 11. A pallet as claimed in claim 10, having a deep-drawing ratio of width : height of any deformation produced by the deep-drawing operation of 5:1 to 1:5.
 12. A pallet as claimed in claim 10, having a deep-drawing ratio of width : height of any deformation produced by the deep-drawing operation of 2.5:1 to 1:2.5.
 13. A pallet as claimed in claim 1, including a continuous or interrupted peripheral rim turned out of the general plane of the pallet.
 14. A pallet as claimed in claim 1, made of polystyrene or polyvinyl chloride or a copolymer of the corresponding monomers. 